In recent years, a solid-state imaging device, in particular, a CMOS (Complementary Metal Oxide Semiconductor) image sensor has been widely installed in electronic equipment such as a mobile phone, a digital still camera, a single-lens reflex camera, a camcorder, a surveillance camera, and the like by taking advantages of low power consumption and high-speed performance. Further, an image sensor having high performance and high image quality, in which even a functional circuit block such as a block for image processing is formed on a chip together with a pixel array unit (pixel unit), is also starting to appear, recently.
Conventionally, as a method of reading a signal from each pixel of a pixel array unit in a CMOS image sensor, there is a technique in which a non-volatile memory is provided in the latter stage of a signal processing unit which digitizes an analog pixel signal read from the pixel, to thereby realize high-speed reading using the non-volatile memory (for example, see Patent Document 1).